1. Field of the Invention
The present invention relates to a processing cartridge, a photoreceptor drum unit, and end member pair, which are used in an image forming apparatus, such as a laser printer or a copier.
2. Description of the Related Art
In an image forming apparatus, such as a laser printer or a copier, a processing cartridge which is attachable to and detachable from a main body (hereinafter, there is a case of being described as “apparatus main body”) of the image forming apparatus, is provided.
The processing cartridge is a member which forms content to be expressed, such as characters or figures, in a posture of being mounted on the apparatus main body, and transfers the content to a recording medium, such as a paper sheet. Therefore, in the processing cartridge, a photoreceptor drum in which the content to be transferred is formed, and charging means or developing means for forming the content to be transferred to the photoreceptor drum, are provided.
Regarding the processing cartridge, the same processing cartridge for maintenance is attached to or detached from the apparatus main body, or an old processing cartridge is disengaged from the apparatus main body for replacing a new processing cartridge, and instead of the old processing cartridge, the new processing cartridge is mounted on the apparatus main body. It is desirable that attachment and detachment of the processing cartridge can be performed by a user of the image forming apparatus, and is performed as easy as possible from such a viewpoint.
In addition, it is necessary that the photoreceptor drum included in the processing cartridge is rotated during the operation. Here, a driving shaft of the apparatus main body is engaged with the photoreceptor drum directly or via another member, and accordingly, an end member is provided so that the photoreceptor drum receives a rotating force from the driving shaft and rotates.
In addition, in this manner, in order to attach and detach the processing cartridge to and from the apparatus main body, it is necessary to release (disengage) the engagement of the driving shaft of the apparatus main body and the end member provided in the photoreceptor drum, and to reengage (mount) the driving shaft and the end member.
Here, when the photoreceptor drum (processing cartridge) can be attached and detached by being moved in the shaft direction of the driving shaft of the apparatus main body, it is relatively easy to configure the apparatus for this. However, from the viewpoint of reducing in size of the image forming apparatus and ensuring an attachment and detachment space of the processing cartridge, it is preferable to disengage the processing cartridge from the apparatus main body to be pulled out in the direction different from the axial direction of the driving shaft, or to mount the processing cartridge to the apparatus main body to be pushed in this direction.
In Patent Document 1 (JP-A-2010-002688), a configuration for attaching and detaching the processing cartridge in the direction which is different from the axial direction of the driving shaft of the apparatus main body, is disclosed. Specifically, a coupling member (shaft member) described in PTL 1 is attached to be swingable to a drum flange (shaft member) by providing a spherical portion. Therefore, a part (rotating force receiving member) which is provided in the coupling member and is engaged with the driving shaft of the apparatus main body, can swing around the spherical portion and change an angle with respect to the axis of the photoreceptor drum, and mounting and disengaging of the driving shaft of the apparatus main body and the photoreceptor drum are easily performed.
Accordingly, the photoreceptor drum included in the processing cartridge can be engaged with the apparatus main body via the coupling member, and can rotate following the driving shaft. However, there is a case where the photoreceptor drum moves in the axial direction and a position thereof is not determined when the engagement is performed, and appropriate engagement cannot be performed. Accordingly, there is a concern that the driving shaft idles and the photoreceptor drum does not rotate, or that an image region of a photoreceptor is not stable, or printing position deviation or color deviation is generated even when the photoreceptor drum rotates.
Meanwhile, according to the configuration of Patent Document 1, for example, as illustrated in FIGS. 24A and 24B of Patent Document 1, an end surface of a bearing member and a rib of a drum frame body come into contact with each other, the movement in the axial direction (longitudinal direction) is regulated by nipping the bearing member (drum flange) from both sides, that is, one side and the other side of the axial direction, and the positioning is performed.
Patent Document 1: JP-A-2010-002688
However, when the movement of the photoreceptor drum in the axial direction is strictly regulated in this manner, during the assembly of the processing cartridge, it is necessary to make the photoreceptor drum unit fitted to a part which does not have enough dimension. Therefore, it is necessary to improve precision of the member, management becomes more strict, and this influences productivity.